A new snake eel species of the genus Ophichthus (Anguilliformes: Ophichthidae) from the southeast coast of India, Bay of Bengal, with the taxonomic account of Ophichthus chilkensis.

A new species of the ophichthid eel of the family Ophichthidae is described based on five specimens collected from the Mudasalodai fish landing center, off Cuddalore coast, southeast coast of India, Bay of Bengal. Ophichthus naevius sp. nov. is distinguished from its congeners by having a unique color pattern: dorsal body with numerous dense dark spots or patches, ventral body pale yellowish green, dorsal-fin origin just before pectoral-fin tip, vertebral formula: 12-14/52-53/134-138, and teeth on jaw uniserial and pointed. The study also reports the range extension and molecular evidence of Ophichthus chilkensis from South India. Molecular analyses were performed for both species, and their phylogenetic relationship suggests that the new species exhibits 10.2% genetic divergence with its congener Ophichthus sangjuensis, followed by Ophichthus brevicaudatus (10.4%), and Ophichthus sp. 1 (11.8%) also forms the closest clade in both Bayesian inference and maximum likelihood (ML) tree. Similarly, according to the topology of the ML tree, the species O. chilkensis forms a clade with Ophichthus sp. 5, Ophichthus remiger, Ophichthus frontalis, Ophichthus sp. 6, and Ophichthus rex, suggesting that it would be the genetically closest congener.

A new species of the conger eel genus Macrocephenchelys from deep waters of the Arabian Sea.

A new species of the genus Macrocephenchelys is described herein based on a single specimen collected from the deep-sea trawl landing at Kalamukku fish landing centre, Kerala coast, Arabian Sea. The new species is distinguished by having a dorsal-fin origin behind the middle of pectoral fin, a larger head, shorter trunk, larger gill opening, dorsal surface of body with dark-brown colour and ventral surface of head and belly with numerous patches of melanophores before anus, vertebrae 14-30-151. The new species shares most of the characteristics with Macrocephenchelys brevirostris but differs from it by having a more anterior dorsal-fin origin (vs. over the tip or slightly behind the pectoral-fin tip), larger head [15.3% total length (TL) vs. 10.5%-13.9% TL, 53.2% pre-anal length (PAL) vs. 35.8%-47.6% PAL], shorter trunk length (13.6% TL vs. 14.4%-20.6% TL, 47.3% PAL vs. 52.4%-66.2% PAL); further it shows 7.9%-8.1% genetic divergence from the sequences of M. brevirostris.

Ariosoma indicum sp. nov., a new species of congrid eel (Anguilliformes: Congridae: Bathymyrinae) from the Indian waters.

Ariosoma indicum sp. nov. is described herein based on 12 specimens [(335-433 mm total length (TL)] collected off the Arabian Sea of southwest coast of India and 7 specimens from Digha Mohana, off the Bay of Bengal of northeast coast of India. The new species is distinguished from congeners in having the following combination of the characters: anus positioned anterior to middle of total length, pre-anal length 40.0%-43.1% of TL; short wedge-shaped pointed vomerine teeth patch, three or four rows in anterior portion, tapering posteriorly with four uniserial teeth; supraorbital canal with four or five pores; pre-dorsal vertebrae 9-10; pre-anal vertebrae 49-53; total vertebrae 141-146; body greenish-brown in colour; extremities of the lower jaw with minute dark pigmentation patches before the rictus, bicoloured pectoral fin. A. indicum shares few characters with the Indian water species, Ariosoma gnanadossi, but readily differs from the latter in having more pre-anal vertebrae (49-53 vs. 47 in A. gnanadossi); fewer lateral-line pores (130-137 vs. 145); shorter tail (54.9%-57.9% TL vs. 60.1% TL); smaller eye (15.1%-17.7% HL vs. 19.2% HL); smaller interorbital width (11.8%-15.7% HL vs. 18.2% HL); longer upper jaw (26.9%-30.2% HL vs. 19.2% HL). In addition, molecular analysis using partial mitochondrial COI gene suggests that A. indicum is genetically closer to Ariosoma maurostigma and Ariosoma melanospilos with a divergence of 15.0% and 15.8%, respectively, and forms a well-supported monophyletic clade.

A new species of the congrid eel genus Ariosoma (Anguilliformes: Congridae) from the south-west coast of India.

A new congrid eel species, Ariosoma maurostigma sp. nov., is described on the basis of 24 specimens collected from the deep-sea trawl by-catch, Kalamukku Fishing Harbour, off Kerala, Arabian Sea. The new species differs from all other congeners in having the following combination of characters: dark mark or spot on the posterodorsal margin of the eyes; dorsal surface of head with two faint darkish bands across the anterior and posterior margin of the eye; origin of the dorsal fin before the pectoral-fin base; short vomerine teeth patch, ST pores 3, 1 median pore and 1 lateral pore on each side just behind the median pore; preanal vertebrae 47-51; precaudal vertebrae 54-57; total vertebrae 136-142; total pores 129-134. The phylogenetic analysis reveals that the new species is closely related to Ariosoma melanospilos and Ariosoma anale, with divergences of 13.8% and 14.9%, respectively.